The present invention relates to a process for the preparation of phenoxy-triazolyl-pinacol-ones which are known to be useful as fungicides and anti-mycotics.
U.S. Pat. No. 3,912,752 discloses the preparation of fungicides corresponding to the formula ##STR3## by several different processes, one of which comprises reacting ##STR4## in which X represents halogen and n is from 1 to 5, with 1,2,4-triazole in a solvent.
Although this synthesis is feasible, there are certain features which significantly affect the cost of producing such fungicides. Specifically, the process taught in U.S. Pat. No. 3,912,752 requires an excess of at least 100% of the expensive triazole. The excess serves as an acid acceptor to carry the reaction forward and to completion. Recovery of the excess triazole on an industrial scale is difficult because the triazole is completely miscible with water and fairly insoluble in most organic solvents which may be used as process solvents, e.g., toluene. Accordingly, some of the expensive triazole is lost in conventional recovery processes. Recovery also poses problems because the recycled triazole is a solid mixed with inorganic salt so that purification of the triazole is necessary before it can be re-used. Triazole losses in the recovery step result in organic waste in process water which water must then be treated at considerable expense.